A switch in disulfide linkage during minicollagen assembly in hydra nematocysts or how to assemble a 150-bar-resistant structure

Hydra minicollagen, the shortest collagen known, is an important component of the nematocyst wall, which has a very high tensile strength. It has an unusual structure, with small and closely related Cys-rich domains at both ends of its chains. Three chains are trimerized by a central collagenous domain. Polyhydroxyproline helices connect the Cys-rich domains with the collagenous domain. The minicollagen precursor contains three internal disulfide bridges in each Cys-rich domain and no disulfide bridges between chains of the same trimeric molecule or between different molecules. Biochemical and structural evidence as well as confocal immunofluorescence microscopy points to disulfide-mediated assembly during maturation of nematocysts.     

Morphological and molecular analysis of the Nematostella vectensis cnidom

The starlet sea anemone Nematostella vectensis is an emerging model organism for developmental and evolutionary biology. Due to the availability of genome data and its amenability to genetic manipulation Nematostella serves as a source for comparative molecular and phylogenetic studies. Despite this fact, the characterization of the nematocyst inventory and of nematocyst-specific genes is still fragmentary and sometimes misleading in this cnidarian species. Here, we present a thorough qualitative and quantitative analysis of nematocysts in Nematostella vectensis. In addition, we have cloned major nematocyst components, Nematostella minicollagens 1, 3 and 4, and show their expression patterns by in situ hybridization and immunocytochemistry using specific antibodies. Our data provides tools and insights for further studies on nematocyst morphogenesis in Nematostella and comparative evolution in cnidarians.     

Neurotoxin localization to ectodermal gland cells uncovers an alternative mechanism of venom delivery in sea anemones

Jellyfish, hydras, corals and sea anemones (phylum Cnidaria) are known for their venomous stinging cells, nematocytes, used for prey and defence. Here we show, however, that the potent Type I neurotoxin of the sea anemone Nematostella vectensis, Nv1, is confined to ectodermal gland cells rather than nematocytes. We demonstrate massive Nv1 secretion upon encounter with a crustacean prey. Concomitant discharge of nematocysts probably pierces the prey, expediting toxin penetration. Toxin efficiency in sea water is further demonstrated by the rapid paralysis of fish or crustacean larvae upon application of recombinant Nv1 into their medium. Analysis of other anemone species reveals that in Anthopleura elegantissima, Type I neurotoxins also appear in gland cells, whereas in the common species Anemonia viridis, Type I toxins are localized to both nematocytes and ectodermal gland cells. The nematocyte-based and gland cell-based envenomation mechanisms may reflect substantial differences in the ecology and feeding habits of sea anemone species. Overall, the immunolocalization of neurotoxins to gland cells changes the common view in the literature that sea anemone neurotoxins are produced and delivered only by stinging nematocytes, and raises the possibility that this toxin-secretion mechanism is an ancestral evolutionary state of the venom delivery machinery in sea anemones.     

Oral health status in a group of the elderly population residing at home

doi: 10.1111/j.1741‐2358.2011.00556.x Oral health status in a group of the elderly population residing at home Objectives: To determine the oral health status and treatment needs of subjects aged 65 years and older residing in different districts of Ankara. Materials and methods: A total of 1300 patients, 751 females and 549 males, age 65 and over with a mean age of 72.8 ± 6.34 were included in this study. The subjects were visited at home and toothbrushing habits, visiting the dentist, tooth loss, denture needs were questioned and body mass index values were recorded. Results: 52.5% of the subjects were completely edentulous, 83.3% subjects reported wearing a removable denture. Females had a higher total tooth loss frequency when compared to males (p < 0.05). Total tooth loss between 65 and 69 ages was 47.3%, and increased to 62.4% among those aged 75 and over (p < 0.05). 16.2% of the subjects had not visited a dentist in the last 10 years, and only 3% visited a dentist for control check‐ups; no gender‐based difference was observed as to the frequency of dental visits (P > 0.05). No significant relationship was found between tooth loss and BMI values (P > 0.05). 46.3% of the subjects had chewing problems. Conclusions: The subjects included in this study showed high tooth loss frequency and poor oral hygiene habits. Education regarding maintenance of oral hygiene and regular dental check up should be stressed for the elderly.     

The nematocyst: a molecular map of the cnidarian stinging organelle

Nematocysts or cnidocysts represent the common feature of all cnidarians. They are large organelles produced from the Golgi apparatus as a secretory product within a specialized cell, the nematocyte or cnidocyte. Nematocysts are predominantly used for prey capture and defense, but also for locomotion. In spite of large variations in size and morphology, nematocysts share a common build comprising a cylindrical capsule to which a long hollow thread is attached. The thread is inverted and coiled within the capsule and may be armed with spines in some nematocyst types. During the discharge of nematocysts following a chemical or mechanical stimulus, the thread is expelled from within the capsule matrix in a harpoon-like fashion. This process constitutes one of the fastest in biology and is accompanied by a release of toxins that are potentially harmful also for humans. The long history of research on Hydra as a model organism has been accompanied by the cellular, mechanistic and morphological analysis of its nematocyst repertoire. Although representing one of the most complex organelles of the animal kingdom, the evolutionary origin and molecular map of the nematocyst has remained largely unknown. Recent efforts in unraveling the molecular content of this fascinating organelle have revealed intriguing parallels to the extracellular matrix.     

Effects of intracerebroventricular administration of irisin on the hypothalamus–pituitary–gonadal axis in male rats

Irisin is a product of fibronectin type III domain-containing protein 5 (FNDC5) and plays an important role in energy homeostasis. In this study, we aimed to determine effects of intracerebroventricular administration of irisin on the hypothalamus–pituitary–gonadal axis by molecular, biochemical, and morphological findings. Fourty male Wistar-Albino rats were used and divided into four groups including control, sham (vehicle), 10, and 100 nM irisin infused groups (n = 10). Hypothalamic gonadotropin releasing hormone (GnRH) level and serum luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone levels were determined. Testicular tissue histology and spermiogram analysis were also performed. Both irisin concentrations significantly reduced hypothalamic GnRH messenger RNA (mRNA) and protein levels (p < 0.05). It was found that serum LH, FSH, and testosterone levels and Sertoli and Leydig cell numbers were decreased by irisin administration (p < 0.05). In addition, irisin administration reduced sperm density and mobility (p < 0.05). However, it did not cause any change in testicular and epididymis weights and tubular diameter. Our results reveal that irisin can play a role in the central regulation of reproductive behavior and also reduces testosterone levels by suppressing LH and FSH secretion. These results suggest that the discovery of irisin receptor antagonists may be beneficial in the treatment of infertility.     

In vitro and histological investigation of antitumor effect of some triazole compounds in colon cancer cell line

1,2,4-Triazoles are used as antifungal, antibacterial, antimicrobial, and antioxidant against some oxidative radical species. Recently, many 1,2,4-triazoles continue to be synthesized. In this study, the effect of the 1,2,4-triazole derivatives on human colon cancer (HT29) was investigated in vitro and in vivo in rats. MTT test was applied to in in vitro experiments. For in vivo study, rats were divided into seven groups as follows: Control group (negative control), azoxymethane (AOM), AOM + cisplatin 15, AOM + L1, AOM + L2, AOM + L3, and AOM + L4. To create colon cancer, the AOM injection was injected subcutaneously at a dose of 15 mg/kg, three times (once weekly). The in vivo studies were completed at 28 weeks. It was found that the 1,2,4-triazole derivatives reduced the cell viability (P < 0.05). In all animals in the experimental groups, mild dysplasia was detected in 100% of the colon mucosal epithelium. Severe dysplasia and adenocarcinoma were observed in L1 groups. As a result, this study determined that the 1,2,4-triazole derivatives exhibit antitumor activity.     

Evolution of complex structures: minicollagens shape the cnidarian nematocyst

The generation of biological complexity by the acquisition of novel modular units is an emerging concept in evolutionary dynamics. Here, we review the coordinate evolution of cnidarian nematocysts, secretory organelles used for capture of prey, and of minicollagens, proteins constituting the nematocyst capsule. Within the Cnidaria there is an increase in nematocyst complexity from Anthozoa to Medusozoa and a parallel increase in the number and complexity of minicollagen proteins. This complexity is primarily manifest in a diversification of N- and C-terminal cysteine-rich domains (CRDs) involved in minicollagen polymerization. We hypothesize that novel CRD motifs alter minicollagen networks, leading to novel capsule structures and nematocyst types.     

Characterization of products from the pyrolysis of rapeseed oil cake

The main aim of this study was to investigate the composition of products from the pyrolysis of rapeseed oil cake in a fixed bed reactor at 400, 450, 500, 700 and 900 degrees C. The gas products mainly consisted of CO(2), CO, CH(4) and H(2)S at 500 degrees C. Empirical formula of bio-oil from the pyrolysis of rapeseed oil cake was CH(1.59)O(0.16)N(0.116)S(0.003) for 500 degrees C. Bio-oils mainly contained oleic acid, 1H-indole, 2,3,5-trimethoxy toluene, toluene, (Z)-9-octadecanamide, psoralene, phenol and phenol derivatives at all pyrolysis temperatures. Both non-aromatic and aromatic hydrocarbon compounds were determined in water phase of liquid product by Headspace-GC analysis. The heating values of bio-chars were found to be similar (24MJkg(-1)) at all pyrolysis temperatures.     

Effect of pericardial fluid pro-inflammatory cytokines on hemodynamic parameters

We investigated the effects of pro-inflammatory cytokines of pericardial fluid on hemodynamic parameters in patients undergoing coronary artery surgery. Seventy-eight patients were included in the study and they were allocated to three groups: group 1, stable angina pectoris (SAP, n = 15); group 2, unstable angina pectoris (USAP, n = 34); group 3, post-myocardial infarction (PMI, n = 29). Pericardial fluid and arterial blood samples were obtained from all patients and interleukin (IL)-1beta, IL-2 receptor, IL-6, IL-8 and tumor necrosis factor-alpha (TNF-alpha) levels were measured. Pericardial IL-1beta concentration (pg/mL) was significantly higher in the USAP group (26.6 +/- 10.9) compared to the SAP (5.0 +/- 0.1) and PMI (5.8 +/- 1.0) groups. IL-2R, IL-6, IL-8 and TNF-alpha concentrations of pericardial fluid were significantly higher than serum in all groups; difference was more prominent in the PMI group compared to the SAP and the USAP groups. Serum IL-1beta concentrations (pg/mL) were significantly higher in the USAP group (21.8 +/- 3.4) compared to the SAP group (5.0 +/- 0.1) and the PMI group (5.4 +/- 1.6). Cardiac index (CI) before opening the pericardial sac was found to be lower in the USAP group (1.6 +/- 0.3 L/min/m2) compared to the SAP (2.2 +/- 0.5 L/min/m2) and the PMI (2.1 +/- 0.5 L/min/m2) groups (p = 0.028 and p = 0.011, respectively). In the USAP group, there was a relationship between reduction of CI and increase of IL-1beta levels in serum and pericardial fluid.